Rectifying apparatus



Aug. 16, 1932. H. s. ANDRE RECTIFYING APPARATUS Original Filed Oct. 1,1926 I jwerig 'i e/z rd 6: 14/? 7'6 W @AMM mmw mim w g 4 N A E, 5:... 5w tlQu .7 ill Patented Aug. 16, 193? I 1,872,214

UNITED STATES PATENT OFFICE 1mm G. mm, or rams, armor:

BEGIII'YIN G .AI'PARATUS Application fled October 1, 1986, Serial No.180,924. Renewed Kay 11, 1931.

The present invention relates to electrical ing the subject of thepresent invention in apparatus and in particular to alternating which,current rectifiers in which two metals of dii- Fi 1 is a verticalsection of the improved ferent character are employed as electrodes,recti er; the metals fulfilling alternately the function Fig. 2 is asection taken on line 2-2 of of cathode and anode. Fig. 1;'

In my Patent No. 1,830,500, dated Novem Fig. 3 represents a verticalsection of anbeer 3, 1931, of which this is a continuation otherembodiment; while in part, I have disclosed a rectifier one elee- Fig. 4shows a section taken on line 4-4.- trode of which comprises a metalliccolloid of Fig. 3. 1 while the other is formed of a material thatReferring to the illustration, the invenwhen subjected to an oxidizingagent yields n in its pr ed m n i ts of glass a compound whichcooperates with the other tube or envelope 2, the ends of which areelectrodes to form a unilateral conductor. o ed by stoppers 3, 14 madeof rubber or 15 In the application identified, I have also bakelite. Theupper stopper has an opening stated thc presence and manner in whichlongltudinally 0f the principal axis of the derived of an element incolloidal form makain r for the introduction of fine tube ing physicalcontact with. one of the electrodes 4 0 n ulafilng material, as glass orrubber. and in particular with the cathode. Aph 'lec lfier properconsists of cathode 13 paratns made according to the foregoing madepreferably 0f cylindrical form t0 fit pecification has the property ofrectifying the diameter 0f tube 2 and Of a material alternating currentof comparatively lar exhibiting strong electrolytic oxidation, foramplitude. example aluminum, nickel or one of its al- It has been foundin practice that the col- QX as nlcke-l-silicoll, containing 25 toloidal element instead of being introduced 1l COI1, and nickel-iron. Thecathod i i physically into the space surrounding th Intimate contactwith colloidal anode 10 th d as l i d i my li ti formed 1n place byelectrolytic action occuru, may b f d i place b th ti f ring 1n a mannerto be described hereinafter. th current t b tifi d th li i ti Referencecharacter 8 deslgnates a conductor a tediou te in ufa tu of material, assilver or graphite, the oxida- Other changes in construction will benoted ti011 p nd f which are good conin the following descripti n, f lductors of electrical energy and able to withwhereas in the applicationr f r d t th stand attack by acid, surfacial oxidation excathode issealed within the surrounding cas epte As will be noted from thedrawing, ing by means of sulphur or other a orph u electrode 8 is ofrectangular cross-section but material, manufacturing experience has mayalso take a cylindrical form and is SUS- shown that other methods ofsecuring the pended in the glass envelope by lead wire 5 cathode arepreferable. passing through fine tube 4. The lead wire is The inventiondescribed hereinafter has preferably of the same metal as the electrodefor its purpose a design of rectifier o erating to which it is attached.

on the colloidal rinciple which 0 ers sim- For electrolyte 6, whichcompletely subplicity of menu acture and ease of operamerges electrode8, I prefer sulfuric acid tion. having concentration of approximatel 66Other features consist in novelty of con- Baum, although it is to beunderstoo that struction combination and arrangement of all fluidscapable of producing oxidation of parts hereinafter described andclaimed, the metals, and any degree of concentration comes advantages ofwhich'will be obvious 'to those within the purview of my invention. Iskilled in the art. In order that the solution may be sufli- Theaccompanying drawing illustrates an ciently strong to prevent permanentelectrolexemplary embodiment of the device form-. ysis and at the same.time, weak enough to preserve the electrodes from dissolution by attack,I combine with the acid an anhydrid in approximately 20% proportion,preferably that of phosphoric acid.

At 7, I have indicated a quantity of glass wool so-called, effectivelyto hold by absorption acid superfluous or in loose form to the end thatthe rectifying unit may be handled without spill. Furthermore, theinterstices between glass fibres allow passage of the gas evolved duringthe initial process of electrolysis as will be explained later. The gasmay escape to the atmosphere through fine tube 4.

Cathode 3 is secured within the envelope by filling 14 of rubber pouredhot in place, or bakelite, which makes firm contact with the glass wallby baking. A seal in addition to element 14 is provided by layer 15 ofplastic compound.

The entire rectifying unit is secured preferably in a base of the Edisonscrew type by plastic material 16 about the periphery of which member 12makes electrical connection by molybdenum lead 17 with the cathode. Itis obvious, however, that under certain conditions a bayonet-slot typeof base may be advantageously employed. The base terminates in metallicmember 19 to which connection is made from the anode by molybdenum lead9. For the purpose of protectmg the unit from external injury and alsoto insure convenience of handling, I provide a container or casing 1 ofa metal, which shapes conveniently, as lead or brass.

This container is open to the atmosphere through apertures 20 andsecured to the base by a close fit in metallic annular ring 11. Inasmuchas the principal roles of the enclosing envelope are those of protectionand the furnishing of a convenient arrangement for making contact withexternal circuits, its shape and form may be varied extensively, and Ido not intend to limit myself to that shown.

The operation of my device is not wholly understood from the theoreticalstandpoint, but I believe it to be as follows:

When alternating current is initially applied to the cathode and anode,electrolytic phenomena take place as evidenced by the evolution of gasin the acid. The silver conductor which initially performs the functionof anode appears to disintegrate and in powdered or colloidal form isattracted to the nickel cathode Where a relatively thick deposit isformed. This deposit is in the nature of a finely divided mass of metal,each particle of which is partially surrounded by liquid.

As indicated on the drawing, the colloid, when examined microscopically,appears to build in a formation resembling the roots of a tree spreadingout from the trunk. This action continues until the entire space betweenanode and cathode is bridged by colloidal arms of irregularcross-section, hav ing their inception at the silver anode. It isapparent, however, that conditions of operation, as voltage and freuency of the electromotive force applied uring the preliminary period,also the size, shape and position of electrodes, each have a markedeffect on the manner in which the powdered mass is obtained.

As representing another form which the colloid may take, in Fig. 3, Ishow an electrode arrangement, i. e. cathode uppermost,

reversed from the position assumed in Fig. 1. Due in part togravitational forces, the particles of silver seem to con regate withoutdefinite outline between the e ectrodes, a portion falling to the bottomof the glass envelope. Inasmuch as the latter and the outer metallicshield form no part of the present invention, I will not describe them.

Referring to Fig. 4, the section of cathode will be noted as a crosswhich shape I have found operates beneficially when the electrodes arein the positions shown.

The action just described extends over a short period of time and is acondition precedent to complete rectification of the appliedelectromotive force, although as a matter of fact I find that partialrectification sets in almost immediately upon application of thealternating potential.

At the expiration of the preliminary colloid forming period,electrolytic action a pears to cease, and as far as I have been ab e todetermine, the rectifier eventually is devoid of electrolysis. In thisspecification I intend electrolysis to include disintegration ofelectrodes by an electrolyte either with or without the formation ordeformation of a superficial oxide layer. The primary function of theelectrolyte, however, is to oxidize the electrodes, which being ofdissimilar metal will be affected unegually. In its subsequent operationas a recti er, the anodal function is transferred to the colloid,electrode 8 assuming the role of a mere conductor or lead.

Now I have found that oxidation compounds of nickel and its alloys havethe desirable characteristic of permitting current flow in one directiononly. This property appears to be utilized to great advantage w enoperating inconjunction with a colloidal anode that forms many points ofphysical contact with the adjacent oxide film, ofiering unilateralconduction of current in aggregate, of a high order.

The passage of current from anode to cathode may be explained on thetheory of transference of atoms of oxygen direct from the nickel tosilver while the insulating property of the nickel oxide film, uponreversal of potential, prevents current passing in the oppositedirection. While the silver is also acted upon by an electrolyte, theresulting compound, oxide of silver, conducts current readily in bothdirections. Thus the rectifying feature is attributed at present solelyto the oxide layer covering the nickelous cathode.

This explanation, however, is offered purely as a matter of interest andwhich present experience with the rectifier has seemed to dictate.

Whatever are the true principles involved, the fact remains that arectifier made according to the specification set forth utilizing anickel-silicon cathode of .093 diameter, a silver anode of .01 squareinches cross-section, on test continuously passed rectified directcurrent of one ampere, delivering a potential of six volts with a lossin the tube of approximately one watt. Such showing, of course, was madeafter the colloid was formed complete and substantially all electrolyticaction had ceased.

While I have illustrated'the electrodes rela- 6. A unidirectionaldischarge device comprising a cathode having an extended ex terior areawith a unilaterally conducting layer and a bilaterally conducting anodein contact with said area reduced to sub-divided form by passage ofcurrent between sa1d anode and said cathode.

Signed by me at Boston, Massachusetts, this 17th day of September, 1926.

HENRI G. ANDRE tively close together, it will be appreciated by thoseskilled in the art, their shape, size and spacing may be varied to meeta specific performance or design. The device disclosed is readilyadapted to operate in conjunction with standard circuits utilizing halfor full wave rectification. For rectification of both half waves it isobvious that two anodes and a cathode or two cathodes and an anode maybe combined for convenience in a single receptacle.

I claim:

1. A unidirectional discharge device having a film-forming electrode andan additional non-filmforming electrode with a mass of finely dividedconducting material substantially bridging the space therebetweencharacterized in that the particle mass comprises a distintegrationproduct ofthe I other electrode and is formed in situ.

2. A unidirectional discharge device comprising a cathode having aunilaterally current conducting layer and a non-film-forming anodeassociated therewith reduced to subdivided form by the action of thecurrent to be rectified.

3. A unidirectional discharge device comprising in combination, acathode, the oxidation product of which constitutes a unilateralconductor of current, an anode Whose oxide is conducting associatedtherewith, a member composed of minute particles formed in place andmaking contact with said cathode and a slightly ionizable liquid toproduce oxidation of the latter.

4. 1m an electrical apparatus, the combination with a non-film-forminganode, of a film forming cathode associated with the said anode andimmersed in an electrolyte whereby gas is evolved, and means forabsorbing the electrolyte including a fibrous material, the strands ofwhich permit gas flow, the said anode being reducible to par-

